Catoptrical-dioptrical device for electric lighting



Oct. I7, 1967 GoYTlsoLo TALTAVULI. @343,037

CATOPTRICAL-DIOPTRICAL DEVICEv FOR ELECTRIC LIGHTING Y Filed Aug. 3, 1965 5 Sheets-Sheet 1 Wanda/0%) vi @wc/ Effe/nys Oct. 17, 1967 l. GoYTlsoLo TALTAVULL. 3,343,937

- CATOPTRICALDIOPTRICAL DEVICE FOR ELECTRIC LIGHTING Filed Aug. s, 1965 sheets-shew` 2 /YWMKLM my@ ZTof/ve sr Oct. 17,'1967 l. GoY'nsoLo TALTAVULL 3,348,937

CATOPTRICAL-DIOPTRICAL DEVICE FOR ELECTRIC LIGHTING Filed Aug. s, 1965 5 sheets-sheet s gmc/O @W50/O 707m# United States Patent 3 348 037 CATOPTRICAL-DIOPRICAL DEVICE FOR ELECTRIC LIGHTING Ignacio Goytisolo Taltavuil, Calle Madrazo 83,

Barcelona, Spain Filed Aug. 3, 1965, Ser. No. 476,867 Claims priority, application'Spain, Nov. 30, 1964, 306,890 4 Claims. (Cl. 24U-41.38)

ABSTRACT F THE DISCLQSURE i An enclosure for a ligh bulb comprises a system of stepped prisms arranged in parallel planes to the equatorial plane of the light. The enclosure comprises a plurality of intercoupled moulded prisms located in contiguous zones to said equatorial plane, the inner sectional surfaces of said prisms on which the luminous rays from said bulb fall having a straight generatrix Vand being essentially parallel to the vertical axis of said bulb, the outer upper surfaces of said prisms from which the luminous rays are totally reflected being flat and inclined to the vertical, and the outer lower surfaces of said prisms being of convex formation, so that the rays reflected from said upper surfaces emerge from said lower surfaces to cross one another and deviate from the longitudinal axis of said bulb without incidence on said prisms located on a lower plane, the lowest part of said enclosure forming an annular body of substantially concave form comprising two superimposed zones, the upper zone of said zone being a single prism whose inner sectional surface constitutes a surface recording a straight generatrix inclined to the vertical and whose outer upper surface is straight and inclined to the vertical, and the outer lower surface of said single prism follows a partially straight and partially concave generatrix, from which the rays emerge to the exterior in divergent directions, the lower zone of said zones having a slightly sinuous inner surface and its outer surface comprising a group of small parallel and successive prisms through which the luminous rays are refracted to form a divergent beam.

The present invention relates to an optical device, for directing the light coming from an electric lamp, composed of systems of stepped prisms of a transparent material that forms a surface of revolution around the axis of symmetry of the light source, the systems of prisms being made up of one, two or more moulded pieces of transparent plastics material Vor of glass and operating by total reflexion and by refraction.

j The invention consists in a catoptrical-dioptrical device for electric lighting comprising, in combination with a stand or support of a light source, a plurality of concave moulded pieces or parts of transparent material that may be co-axially joined at their edges to form a block, cons tituting a system of stepped prisms formed by surfaces of revolution centred on the axis of symmetry of the lamp, with straight and curved generatrices, the said prisms being situated in parallel planes with respect to the equator of the lamp, of which prisms those situated above have larger dimensions than the rest of the prisms and are so arranged that light rays proceeding from the lamp and falling on the inner surfaces of the prisms are conducted to the outer faces of the prisms where the rays suffer total. reflection and emerge through the lower faces of the prisms, through surfaces of revolution of curved or straight generatrix, but without the light flux emerging from a first prism coming to fall onto the prism immediately below it, the rays being refracted at the said lower faces, Whilst the prisms situated on parallel planes lower down are of smaller dimensions and work only by refraction.

3,348,037 Patented oci. 17, 1967 This device is characterised by its good performance in using to the best advantage the light flux, which is, for the most part, collected by the prisms so that a more or less open curve of light distribution may be obtained, according to whether the device is of the so-called extensive or intensive type, also enabling to avoidance of glare outside the cone of light produced by the apparatus.

The invention will be further described with reference to the accompanying drawings, in which:

FIGURE 1 shows a lighting fitting embodying the invention and seen partly in section and partly from the outside, including one form of my device consisting of moulded transparent plastics pieces, one cylindrical part, and means for fixing the device to the lamp, and in which the trajectories of the light rays through the device are shown, the prisms in this case providing an intensive curve of light distribution;

FIGURE 2 represents the fitting of FIGURE 1 seen from the top;

FIGURE 3 shows in detail the profile of the section of a totally reflecting prism of the device;

FIGURE 4 shows the mounting of the fitting on a vertical surface, for which purpose it is provided with a jointed support to facilitate the directing of the light beam; and

FIGURE 5 shows the fitting adapted for installing in the open.

FIGURE 1 shows a lighting fitting including a lightdirecting device embodying the invention and consisting of three moulded pieces 1, 5, and 6 of a transparent plastics material, each having the form of a body of revolution. The three pieces are coaxial and on their axis a filament lamp 8 is supported in a suitable holder.

The bottom piece 1 is below the equatorial plane of the lamp corresponding to the plane of the filament, and it consists of a large upper prism 2 and the whole of which is situated below the said equatorial plane, and of several small lower prisms such as 3 and 4 forming a stepped surface, the whole piece ending in a lower opening 20. Each of the upper moulded pieces 5 and 6 is formed by a single large prism situated on the equatorial zone of the lamp or above it at a height varying according to circumstances. Above the top piece v6 there is a cylindrical shade 7 of a transparent or translucent material. Each of the pieces is designed so that it is individually easy to mould, ease of manufacture being the reason why the apparatus consists of various parts put together to form one whole unit.

The detail of the section in FIGURE 1 shows the shape of the prism 2 of the piece 1, which produces total reflexion and diverging emission; the inner face of prism 2 is a truncated cone with a straight generatrix line inclined at a certain angle from the vertical, the outside face also .being a truncated cone with a generatrix inclined at a different angle and in the opposite direction to the vertical, and there is a lower face with a generatrix line partly straight and partly concave, the curved part of the generatrix being a circular curve having its centre in the lower part of the drawing. The shape is such that a rayl R1 issuing from the light source is refracted at the inner face, sustains total internal reflexion on the outer face,

and emerges as ray R1 through the lower face after be-A cording to the trajectories shown in the drawing, coming out as U1', U2', U3', U4', inclined. to the degree that may be seen in the drawing, the rays U1' and U2 converging on each other and the rays U2' and U3' diverging from each other, all this being in order to obtain the requisite curve for the distribution ofthe light.

As regards the single Yprisms of parts 5 and 6, which produce total reflexion and converging emission, each of them has an inner face which is a frusto-conical surface with a straight generatrix somewhat inclined towards the vertical; as to the outer face, it may be a truncated cone Y of straight generatrix inclined towards the vertical, but at a greater angle, or else a surface of revolution with a curved generatrix; the lower face is a surface having a convex generatrix that may consist'of circular arcs ofV different radius and with centres in the upper part of the figure, or else the generatrix may be a mixture of straight and curved lines. The prisms are such that the rays S1, S2, T1, T2, are refracted at the inner surface, suffer total reflexion at the outer surface, and are refracted at the lower surface, emerging as the rays S1', S2', T1', T 2'; the rays issuing from the same prism cross soon after leaving it, in order that the rays leaving the inner part of the prism do not fall on the prism immediately below.V

The cylindrical shade 7 collects the light flux coming from the upperV part of the lamp, and enables the producing of a certain amount of indirect lighting, it may be coloured, transparent .or translucent, thus serving the purpose of an element of decoration. It also produces Va cooling current for the apparatus and the lamp by acting as a chimney. This current is illustrated in the drawing by the arrows F1, F2. The shade 7 can also be in other suitable shapes, especially the lfrusto-conical form.

As the prisms 2, 5 and 6, that work by total reection, are the ones that collect the greater amount of the light ilux,`the light distribution in the emitted beam depends on their relative dimensions and their geometrical'shape, especially at the bottom, that is to say, where the rays issue by refraction, for which reason the lower faces may be more Vor less convex in the prisms 5 and 6, thus producing a converging emission, and concave or at formed prism 2, so as to obtain a diverging emission of the rays of light fro mthe same prism, the prisms shown in the drawings being merely examples of the various forms that may be adopted. It must be borne in mind that from each of light from the same prism, the prisms shown in the superposing of which cones produces a total cone of light, thus producing a distribution of light according to the direction given it and the form required.

As shown in FIGURES 1 and 2, a piece 12 that serves as a means of union between the shade 7 and the stand or support of the lamp, is fixed by a nut 13 situated at a determined point on a screwed spigot 14 and is fastened by a lock-nut 15; by adjusting the position of piece 12 on spigot 14 it becomes possible to place the centre of the lamp 8 at the right height so that the centre of emission of the light from the light source is in the very best place. The piece -6 is attached to the shade 7 by means of a bolt 9 that joins the-lower part of the shade 7 to an edge flange 10V of the piece 6. The piece 5 is joined to 6 by the surface of contact with a flange 11, and the same occurs between pieces 1 and 5, it thus being possible to use as a joining element a solvent or a special cement for plastic material, or else a similar type of bolt to that joining pieces V6 and 7. Three spider arms 16 support the shade 7 from the central piece 12.

FIGURE 3 shows in detail the shape of the upper prismatic variant 5 of FIGURE 1 and the trajectory of the luminous rays through it when it is a question of giving it a shape that permits the maximum reduction of the amount of material in the piece. For this purpose,

consequently this characteristic makes the outer ,profile` Y prisms on which the luminous rays from said bulb fallY Vbeing retracted at an angle M with regard to the normal to that face 18; the refracted ray V4 falls onto` the outer face 17 at an angle'N with regard to the normal to the said face 17, angle N being `slightly greater Vthan, the angle Ylimit of the transparent substance, so Vthat the `ray V4' suffers total reflexion; the reflected Yray V4" falls onto the lower face 19 at an angle P to the normal to the said face, which face is a surface of revolution with a generatrix formed by a straight line and a curve, and is emitted as ray V4"' by refraction at an angle Q to the normal. If we arrange thatV the angle N be constant, then the complementary angle -N will also be constant, and

17 of the prism correspondV to the so-called logarithmicspiral curve. The angle N being constant for all the incident rays V0', V1', V2', V3', and V4', it cornesV about.

that those rays once reected tend to converge towards a centre situated on theV lower part of the drawing and the rays emerging on the outside will cross each other at a little distanceV from the surface of the device.

FIGURE 4 lshows the fitting' supported by an articulated device 22 including an arm 23 articulated to a piece 24 which is fixed in the screwed spigot 14, by means of which articulation the inclination of the axis of the fitting can be varied, and'in this way the light beam be sent in the desired direction.

FIGURE 5 shows the fitting adapted for outdoor use and for this purpose there has been added toit a cover 21 affording protection from the rain.

I claim:

a supportfor said bulb, and an enclosure for said bulb of transparent material comprising a system of stepped prisms arranged in parallel planes to that of the equatorial plane of said bulb consisting of a plurality of intercoupled moulded prisms located in contiguous zones to said equatorial plane, the inner sectional surfaces ofV Said having a straight generatrix and being essentially parallel to the vertical axis of said bulb, the outer upper surfaces of said prisms from which the luminous rays are totally reected being flat and inclined to the vertical, andthe outer lowerV surfaces of said prisms being of convex formation, so that the rays'rellected from said upper surfaces emerge from said lower surfaces to cross one an-` other and deviate from the longitudinal axis of said bulbwithout incidence on said prisms located on a lower plane, the lowest part of said Venclosure forming an annular body of substantially concave form comprising two superimposed zones, the upper zone of said zones being a single prism whose inner sectional surface constitutesy a surface recording a straight generatrix inclined to the vertical and whose outer upper surface is straight and inclined to the vertical, and the outer lowerA surface of said single prism follows a partially straight and partially concave generatrix, from which the rays emerge to the exterior in divergent directions, lthe lower zone of said zones having a slightly sinuous inner surface and its'outer surface comprising a group of small parallel and successive prisms through which the luminous rays are refracted to form a divergent beam. Y

2. A device as set forth in claim 1 wherein Ysaid prisms are moulded in ring form and means are provided for@ interconnecting said prisms.

3. A device as set forthin claim 1 wherein each of said prisms comprise a prism of revolution and are pro-V vided with a flange at their inner surfaces to overlap and be secured to a neighbouring prism to form ablock.

4. A catoptrical-dioptrical device having a lamp bulb, a support for said bulb, and an enclosure for said bulb of transparent material comprising a system of stepped prisms arranged in parallel planes to that of the equatorial plane of said bulb consisting of a plurality of intercoupled moulded prisms located in contiguous zones to said equatorial plane, the inner sectional surfaces of said prisms on which the luminous rays from said bulb fall having a straight generatrix and being essentially parallel to the vertical axis of said bulb, the outer upper surfaces of said prisms from which the luminous rays are totally reflected are convex and traced by points corresponding to a logarithmic spiral, and the outer lower surfaces of said prisms being of convex formation, so that the rays reflected from said upper surfaces emerge from said lower surfaces to cross one another and deviate from the longitudinal axis of said bulb without incidence on said prisms located on a lower plane, the lowest part of said enclosure forming an annular body of substantially concave form comprising two superimposed zones, the upper zone of said zones being a single prism whose inner sectional surface constitutes a surface recording a straight generatrix inclined to the vertical and whose outer upper surface is straight and inclined to the vertical, and the outer lower surface of said single prism follows a partially straight and partially concave generatrix, from which the rays emerge to the exterior in divergent directions, the lower zone of said zones having a slightly sinuous inner surface and its outer surface comprising a group of small parallel and successive prisms through which the luminous rays are refracted to form a divergent beam.

References Cited UNITED STATES PATENTS 538,193 4/1895 Fredureau 240-106 1,551,274 8/ 1925 Townsend 240-93 2,062,772 12/1936 Surface 240-78 2,656,453 10/1953 Segil 24U-51.12 2,697,777 12/1954 Rosa 24U-51.12

FOREIGN PATENTS 371,725 6/1907 France.

581,751 l/ 1924 France.

786,724 6/ 1935 France.

749,999 5/ 1944 Germany.

20,734 2/ 1896 Great Britain.

376,831 7/1932 Great Britain.

NORTON ANSHER, Primary Examiner. WYNDHAM M. FRYE, Assistant Examiner. 

1. A CATOPTRICAL-DIOPTRICAL DEVICE HAVING A LAMP BULB, A SUPPORT FOR SAID BULB, AND AN ENCLOSURE FOR SAID BULB OF TRANSPARENT MATERIAL COMPRISING A SYSTEM OF STEPPED PRISMS ARRANGED IN PARALLEL PLANES TO THAT OF THE EQUATORIAL PLANE OF SAID BULB CONSISTING OF A PLURALITY OF INTERCOUPLED MOULDED PRISMS LOCATED IN CONTIGUOUS ZONES TO SAID EQUATORIAL PLANE, THE INNER SECTIONAL SURFACES OF SAID PRISMS ON WHICH THE LUMINOUS RAYS FROM SAID BULB FALL HAVING A STRAIGHT GENERATRIX AND BEING ESSENTIALLY PARALLEL TO THE VERTICAL AXIS OF SAID BULB, THE OUTER UPPER SURFACES OF SAID PRISMS FROM WHICH THE LUMINOUS RAYS ARE TOTALLY REFLECTED BEING FLAT AND INCLINED TO THE VERTICAL, AND THE OUTER LOWER SURFACES OF SAID PRISMS BEING OF CONVEX FORMATION, SO THAT THE RAYS REFLECTED FROM SAID UPPER SURFACES EMERGE FROM SAID LOWER SURFACES TO CROSS ONE ANOTHER AND DEVIATE FROM THE LONGITUDINAL AXIS OF SAID BULB WITHOUT INCIDENCE ON SAID PRISMS LOCATED ON A LOWER PLANE, THE LOWEST PART OF SAID ENCLOSURE FORMING AN ANNULAR BODY OF SUBSTANTIALLY CONCAVE FORM COMPRISING TWO SUPERIMPOSED ZONES, THE UPPER ZONE OF SAID ZONES BEING A SINGLE PRISM WHOSE INNER SECTIONAL SURFACE CONSTITUTES A SURFACE RECORDING A STRAIGHT GENERATRIX INCLINED TO THE VERTICAL AND WHOSE OUTER UPPER SURFACE IS STRAIGHT AND INCLINED TO THE VERTICAL, AND THE OUTER LOWER SURFACE OF SAID SINGLE PRISM FOLLOWS A PARTIALLY STRAIGHT AND PARTIALLY CONCAVE GENERATRIX, FROM WHICH THE RAYS EMERGE TO THE EXTERIOR IN DIVERGENT DIRECTIONS, THE LOWER ZONE OF SAID ZONES HAVING A SLIGHTLY SINUOUS INNER SURFACE AND ITS OUTER SURFACE COMPRISING A GROUP OF SMALL PARALLEL AND SUCCESSIVE PRISMS THROUGH WHICH THE LUMINOUS RAYS ARE REFRACTED TO FORM A DIVERGENT BEAM. 